Elastic Turbulence in Channel Flows at Low Reynolds number

Boyang Qin, Paulo E. Arratia

Published 2016-09-27Version 1

We experimentally demonstrate the existence of elastic turbulence in straight channel flow at low Reynolds numbers. Velocimetry measurements show non-periodic fluctuations in the wake of curved cylinders as well as in a parallel shear flow region. The flow in these two locations of the channel is excited over a broad range of frequencies and wavelengths, consistent with the main features of elastic turbulence. However, the decay of the initial elastic turbulence around the cylinders is followed by a growth downstream in the straight region. The emergence of distinct flow characteristics both in time and space suggests a new type of elastic turbulence, markedly different from that near the curved cylinders. We propose a self-sustaining mechanism to explain the sustained fluctuations in the parallel shear region.